Electronic State Modulation and Reaction Pathway Regulation on Necklace‐Like MnOx‐CeO2@Polypyrrole Hierarchical Cathode for Advanced and Flexible Li–CO2 Batteries

• Published in: Advanced energy materials 2022-04, Vol.12 (14), p.n/a
• Main Authors: Deng, Qinghua, Yang, Yong, Mao, Chunfeng, Wang, Tianyu, Fang, Zhao, Yan, Wuwei, Yin, Kai, Zhang, Yiwei
• Format: Article
• Language: English
• Subjects: bimetal oxide; Carbon dioxide; catalytic cathodes; Cathodes; Cerium oxides; Conducting polymers; conductive polymers; Density functional theory; Electron states; Electronic structure; Energy storage; freestanding; Li–CO 2 batteries; Nanospheres; Polypyrroles; Substrates
• ISSN: 1614-6832; 1614-6840
• DOI: 10.1002/aenm.202103667

Li–CO2 batteries provide the possibility for synchronous implementation of carbon neutrality and development of advanced energy storage devices. Catalytic cathodes composed of well‐designed conductive substrates and active materials are critical to the improvement of Li–CO2 batteries. Herein, MnOx‐CeO2 hollow nanospheres are strung together by conductive polypyrrole (PPy) via post‐in‐situ polymerization, and a necklace‐like MnOx‐CeO2@PPy hierarchical cathode with excellent flexibility and self‐supporting feature is constructed. Benefitting from the excellent conductivity of PPy, the binder‐free structure, and the greatly exposed catalytic active sites, the MnOx‐CeO2@PPy based Li–CO2 batteries exhibit superior discharge capacity (13631 mA h g–1 at 100 mA g–1) and cycle performance (253 cycles) as well as a low overpotential of 1.49 V. Of particular note, the flexible freestanding film is confirmed as a potential catalytic cathode for flexible Li–CO2 batteries. The density functional theory calculations, combined with experimental tests, are performed to gain insights into the enhanced substrate adsorption capacity, the optimized electronic structure of the active surface MnOx‐CeO2 (111), the concentrated electrons on the reaction sites Ce, and the electrochemical mechanism. This work initiates the use of conductive polymers for catalytic cathodes in Li–CO2 batteries, which provide new opportunities for promoting the performance of various energy storage devices. A MnOx‐CeO2 hollow nanosphere is strung together by conductive polypyrrole (PPy) via post‐in‐situ polymerization, and a necklace‐like MnOx‐CeO2@PPy hierarchical cathode with self‐supporting feature is constructed for advanced and flexible Li–CO2 batteries. The related electrochemical mechanism is discussed by combining density functional theory calculations with experimental tests in detail.